Quantum/Machines/SQC 11-Qubit Atom Processor
Australia · operational · Silicon spin
SQC 11-Qubit Atom Processor
SQC 11-Qubit Atom Processor is a silicon spin quantum computer operated by Silicon Quantum Computing in Australia. It has 11 physical qubits. It ranks 2 of 5 silicon spin machines in this table by physical qubit count. 6 sourced specs are in the spec sheet. 3 published benchmark or milestone records are listed below, each marked by who measured it.
Also known as Silicon Quantum Computing 11-qubit phosphorus atom processor
Laboratory processor from Silicon Quantum Computing and UNSW Sydney, posted to arXiv on 4 June 2025 and published in Nature on 17 December 2025. Each register is hyperfine-coupled to a shared electron and the two electrons are exchange-coupled, with atoms placed by hydrogen lithography under about 45 nm of encapsulation and operated in a cryogen-free dilution refrigerator at about 16 mK. Gate fidelities run from 99.10 to 99.99 percent (single-qubit above 99.90 except one nucleus, nuclear CZ 99.90 percent, electron CROT 99.64 percent), nuclear Hahn-echo T2 spans 3 to 660 ms, and entanglement is shown for up to eight nuclear spins; a 3-qubit GHZ state reached 90.8 percent. No readout fidelity is reported, and the paper describes a research device, not a commercially deployed machine.
Spec sheet
Technical details as the builder or a paper states them, each with its own source. A blank is a fact we could not source, not a zero. Fidelity and coherence figures are in the benchmark table below.
| Spec | Value | Basis | Note | Source |
|---|---|---|---|---|
| Processor | 11-qubit atom processor: 9 phosphorus nuclear spins in two registers plus 2 electron-spin ancillas | Peer reviewed | Nature paper of 2025-12-17. | pmc.ncbi.nlm.nih.govarxiv.org |
| Qubit type | nuclear spins of phosphorus atoms in isotopically purified silicon-28 | Peer reviewed | pmc.ncbi.nlm.nih.gov | |
| Topology | Two registers of 4 and 5 nuclei, each coupled to a shared electron, electrons exchange-coupled | Peer reviewed | pmc.ncbi.nlm.nih.gov | |
| Cooling and environment | Cryogen-free dilution refrigerator, base temperature about 16 mK | Peer reviewed | pmc.ncbi.nlm.nih.gov | |
| Operating temperature | 16 mK | Peer reviewed | Base temperature reported in the paper. | pmc.ncbi.nlm.nih.gov |
| Fabrication | Hydrogen-resist lithography atom placement with about 45 nm silicon encapsulation | Peer reviewed | pmc.ncbi.nlm.nih.gov |
Published benchmark figures
These are numbers the builder or a paper reports for this machine, not results from a common test. The basis column says who measured them. What the metrics mean and why they are not comparable across technologies.
| Metric | Value | Measured | Basis | Note | Source |
|---|---|---|---|---|---|
| Single-qubit gate fidelity | 99.99% | 2025-12-17 | Peer reviewed | Best single-qubit fidelity (nucleus n5); other nuclei above 99.90 except n4. | pmc.ncbi.nlm.nih.gov |
| Dephasing time (T2) | 660000 µs | 2025-12-17 | Peer reviewed | Best nuclear-spin Hahn-echo T2 of 660 ms (range 3 to 660 ms). | pmc.ncbi.nlm.nih.gov |
| Two-qubit gate fidelity | 99.9% | 2025-12-17 | Peer reviewed | Nuclear CZ fidelity 99.90(4) percent; electron CROT is 99.64(8) percent. | pmc.ncbi.nlm.nih.gov |
Timeline
- 2025-06-04: Announced
- 2025-12-17: Status checked: operational
Comparable silicon spin machines
Closest in physical qubit count within the same technology. Counts of different qubit types are not interchangeable across technologies.
| Machine | Operator | Qubits | Status |
|---|---|---|---|
| Intel Tunnel Falls | Intel | 12 | operational |
| Diraq Equinix Sydney System | Diraq | 8 | under construction |
| Equal1 Bell-1 | Equal1 | 6 | operational |
| JAQUI-5 | Forschungszentrum Julich | 5 | operational |